JPWO2020071490A1 - Packaging materials for power storage devices, power storage devices, and methods for manufacturing them. - Google Patents

Abstract

Despite the fact that a layer containing a material capable of forming an image is provided between the base material layer and the barrier layer, it has high adhesion between the base material layer and the barrier layer and laser light. Provided is a packaging material for a power storage device that suppresses deterioration of the base material layer 1 due to irradiation with a laser beam without having to increase the output of. It is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order, and the adhesive layer is in contact with the barrier layer and is bonded. The agent layer is a packaging material for a power storage device, which contains a material capable of forming an image by irradiation with laser light.

Description

The present invention relates to a packaging material for a power storage device, a power storage device, and a method for manufacturing the same.

Conventionally, various types of power storage devices have been developed, but in all power storage devices, a packaging material is an indispensable member for sealing a power storage device element such as an electrode or an electrolyte. Conventionally, metal packaging materials have been widely used as packaging for power storage devices.

On the other hand, in recent years, with the improvement of high performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., various shapes are required for power storage devices, and thinning and weight reduction are required. However, the metal packaging material for a power storage device, which has been widely used in the past, has a drawback that it is difficult to keep up with the diversification of shapes and there is a limit to weight reduction.

Therefore, in recent years, as a packaging material for a power storage device that can be easily processed into various shapes and can be made thinner and lighter, a base material layer on the outer layer side, a barrier layer, and a thermosetting resin layer on the inner layer side are used. A film-like laminate in which and is sequentially laminated has been proposed (see, for example, Patent Document 1). In such a packaging material for a power storage device, a recess is generally formed by cold molding, and a storage device element such as an electrode or an electrolytic solution is arranged in the space formed by the recess to form a thermosetting resin. By heat-sealing the layers together, a power storage device in which the power storage device element is housed inside the packaging material for the power storage device can be obtained.

In various packaging materials composed of the above-mentioned laminates, ink is printed on the surface of the base material layer to form barcodes, patterns, characters, etc., and adhered onto the base material layer on the printed side. A method of printing on a packaging material (generally referred to as back printing) is widely adopted by a method of laminating an agent and a barrier layer. However, if such a printed surface exists between the base material layer on the outer layer side and the barrier layer, the adhesion between the base material layer and the barrier layer is lowered, and delamination is likely to occur between the layers. In particular, since a high safety is required for a power storage device to which a packaging material for a power storage device is applied, such a method of printing by back printing is avoided in the packaging material for a power storage device. Therefore, conventionally, when printing a bar code or the like on a packaging material for a power storage device, a method of attaching a sticker on which the printing is formed to the surface of an outer layer is generally adopted.

However, when the printed seal is attached to the surface of the outer layer, the thickness and weight of the packaging material for the power storage device are increased. Therefore, in consideration of the recent tendency of the packaging material for a power storage device to become thinner and lighter, there is also a method of printing directly on the surface of the outer layer of the packaging material for a power storage device by printing ink.

As a method of printing directly on the surface of the outer layer of the packaging material for a power storage device by printing ink, for example, pad printing (also referred to as tampo printing) and inkjet printing are known. Pad printing is the following printing method. First, the ink is poured into the recess of the flat plate on which the pattern to be printed is etched. Next, the silicon pad is pressed from above the recess to transfer the ink to the silicon pad. Next, the ink transferred to the surface of the silicon pad is transferred to the object to be printed to form a print on the object to be printed. In such pad printing, since the ink is transferred to the object to be printed using an elastic silicon pad or the like, it is easy to print on the surface of the packaging material for the power storage device after molding, and the power storage device element is used for the power storage device. It has the advantage that it can be printed on the power storage device after being sealed with a packaging material. It also has the same advantage in inkjet printing.

However, when printing is performed directly on the surface of the outer layer of the packaging material for a power storage device with ink, the printing may be peeled off if an organic solvent or the like adheres to the printed portion or the printed portion is rubbed in the subsequent process. Is likely to occur.

Japanese Unexamined Patent Publication No. 2008-287971

Instead of printing on the surface of the outer layer of the packaging material for a power storage device with ink, a material that enables an image to be formed on the packaging material for a power storage device by irradiating a laser beam between the outer layer and the barrier layer is included. There is also a method of forming an image inside a base material layer of a packaging material for a power storage device by providing a print layer and irradiating the print layer with a laser beam.

However, when a printing layer containing a material capable of forming an image is provided on the packaging material for a power storage device by irradiation with laser light, there is a problem that the adhesion between the base material layer and the barrier layer is lowered. That is, the printing layer is a layer that contains a material that enables image formation and is formed thinly. Since the content of the binder resin is low and the adhesiveness is poor, the printing layer is formed between the base material layer and the barrier layer. If is provided, the adhesion is lowered. Further, in order to solve the problem of deterioration of adhesion due to the provision of the print layer, for example, if an adhesive layer is provided between the print layer and the barrier layer, the number of manufacturing steps of the packaging material for the power storage device and the power storage device increases. There is a problem of doing.

Further, even when a print layer containing a material capable of forming an image by irradiation with a laser beam is not provided, an image can be formed by increasing the output of the laser beam, but the minimum amount of the laser beam capable of appropriately forming an image can be formed. There is also a problem that when the output becomes large, the base material layer through which the laser light is transmitted tends to deteriorate.

Under such circumstances, in the present invention, although a layer containing a material capable of forming an image is provided between the base material layer and the barrier layer, the space between the base material layer and the barrier layer is provided. Since it has high adhesion and it is not necessary to increase the output of the laser beam (the minimum output of the laser beam capable of appropriately forming an image can be reduced), the basis for image formation using the laser beam. The main purpose is to provide a packaging material for a power storage device in which deterioration of a material layer is suppressed. Another object of the present invention is to provide a method for manufacturing a packaging material for a power storage device, a power storage device using the packaging material for a power storage device, and a method for manufacturing a power storage device.

The present inventor has made diligent studies to solve the above problems. As a result, it is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order, and the adhesive layer is in contact with the barrier layer, and the adhesive The packaging material for a power storage device containing a material whose layer can form an image by irradiation with a laser beam is provided with a layer containing a material capable of forming an image between a base material layer and a barrier layer. However, since it has high adhesion between the base material layer and the barrier layer and it is not necessary to increase the output of the laser beam, deterioration of the base material layer due to image formation using the laser light is suppressed. I found. The present invention has been completed by further studies based on these findings.

That is, the present invention provides a packaging material for a power storage device and a power storage device according to the following aspects.
Item 1. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package made of a packaging material for the power storage device.
The packaging material for a power storage device is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order.
The adhesive layer is in contact with the barrier layer and is in contact with the barrier layer.
The adhesive layer is a power storage device containing a material capable of forming an image by irradiation with laser light.
Item 2. Item 2. The power storage device according to Item 1, wherein the adhesive layer contains 0.1 to 50% by mass of the material whose image can be formed by irradiation with laser light.
Item 3. Item 2. The power storage device according to Item 1 or 2, wherein the material capable of forming an image by irradiation with a laser beam contains a bismuth-based compound.
Item 4. Item 3. The power storage device according to any one of Items 1 to 3, wherein the material capable of forming an image by irradiation with a laser beam contains a black pigment.
Item 5. Item 2. The power storage device according to any one of Items 1 to 4, wherein an image is formed on the adhesive layer.
Item 6. Item 2. The power storage device according to any one of Items 1 to 5, wherein the adhesive strength between the base material layer and the barrier layer is 3N / 15 mm or more.
Item 7. Item 2. The power storage device according to any one of Items 1 to 6, wherein an image is formed on the adhesive layer.
Item 8. Item 2. The power storage device according to any one of Items 1 to 6, wherein an image visible from the outside is formed.
Item 9. It is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order.
The adhesive layer is in contact with the barrier layer and is in contact with the barrier layer.
The adhesive layer is a packaging material for a power storage device, which comprises a material capable of forming an image by irradiation with a laser beam.
Item 10. At least, it includes a step of laminating a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order.
The adhesive layer is in contact with the barrier layer and is in contact with the barrier layer.
The adhesive layer contains a material that enables an image to be formed by irradiation with a laser beam.
A method for manufacturing packaging materials for power storage devices.
Item 11. Item 9. A housing step of accommodating a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte in a package made of the packaging material for a power storage device according to Item 9.
A step of irradiating the adhesive layer with a laser beam to form an image before or after the accommodating step.
A method of manufacturing a power storage device.
Item 12. Item 2. The method for manufacturing a power storage device according to Item 11, wherein the laser light is a YAG laser light, a YVO ₄ laser light, or a fiber laser light.

According to the present invention, high adhesion between the base material layer and the barrier layer is maintained even though a layer containing a material capable of forming an image is provided between the base material layer and the barrier layer. In addition, since it is not necessary to increase the output of the laser beam, it is possible to provide a packaging material for a power storage device in which deterioration of the base material layer due to image formation using the laser beam is suppressed. Further, according to the present invention, it is also possible to provide a method for manufacturing the packaging material for the power storage device, a power storage device using the packaging material for the power storage device, and a method for manufacturing the power storage device.

It is a schematic diagram which shows an example of the cross-sectional structure of the packaging material for a power storage device of this invention. It is a schematic diagram which shows an example of the cross-sectional structure of the packaging material for a power storage device of this invention. It is a schematic diagram which shows an example of the cross-sectional structure of the packaging material for a power storage device of this invention. SEM image (scanning electron microscope) of a cross section (a portion irradiated with a laser) of a base material layer (biaxially stretched iron film) / adhesive layer / barrier layer (aluminum alloy foil) in the packaging material for a power storage device of Example 1. It is an image of observing the cross section in.

The packaging material for a power storage device of the present invention is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order, and the adhesive layer includes a barrier layer. It is in contact with the adhesive layer and is characterized by containing a material capable of forming an image by irradiation with a laser beam. Hereinafter, the packaging material for the power storage device of the present invention, the method for manufacturing the packaging material for the power storage device, the power storage device using the packaging material for the power storage device, and the method for manufacturing the power storage device will be described in detail.

In the present specification, with respect to the numerical range, the numerical range indicated by "~" means "greater than or equal to" and "less than or equal to". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. 1. Laminated structure of packaging material for power storage device As shown in FIGS. 1 to 3, the packaging material for power storage device of the present invention has at least a base material layer 1, an adhesive layer 2, a barrier layer 3, and a thermosetting resin. It is composed of a laminate having layers 4 in this order. In the packaging material for a power storage device of the present invention, the base material layer 1 is on the outermost layer side, and the thermosetting resin layer 4 is on the innermost layer. That is, when the power storage device is assembled, the heat-sealing resin layers 4 located on the periphery of the power storage device element are heat-sealed to each other to seal the power storage device element, thereby sealing the power storage device element.

In the packaging material for a power storage device of the present invention, the adhesive layer 2 is in contact with the barrier layer 3. Further, the adhesive layer 2 may or may not be in contact with the base material layer 1. For example, an adhesive layer containing no material that enables image formation may exist between the base material layer 1 and the adhesive layer 2. It is not necessary to improve the adhesion between the base material layer 1 and the barrier layer 3 via the adhesive layer 2 and increase the output of the laser beam, and the deterioration of the base material layer 1 due to image formation using the laser light. The adhesive layer 2 is preferably in contact with the base material layer 1 from the viewpoint of suppressing the above.

As shown in FIGS. 2 and 3, the packaging material for a power storage device of the present invention adheres between the barrier layer 3 and the thermosetting resin layer 4 as necessary for the purpose of enhancing their adhesiveness. The layer 5 may be provided. Further, as shown in FIG. 3, a surface coating layer 6 may be provided on the outside of the base material layer 1 (the side opposite to the thermosetting resin layer 4), if necessary.

The thickness of the laminate constituting the packaging material 10 for the power storage device of the present invention is not particularly limited, but from the viewpoint of reducing the thickness of the packaging material for the power storage device and increasing the energy density of the power storage device, for example, 180 μm. Hereinafter, it is preferably 150 μm or less, more preferably about 60 to 180 μm, still more preferably about 60 to 150 μm.

2. 2. Each layer forming a packaging material for a power storage device [base material layer 1]
In the present invention, the base material layer 1 is a layer provided for the purpose of exerting a function as a base material of a packaging material for a power storage device. The base material layer 1 is located on the outer layer side of the packaging material for the power storage device.

The material forming the base material layer 1 is not particularly limited as long as it has a function as a base material, that is, at least has an insulating property. The base material layer 1 can be formed using, for example, a resin, and the resin may contain an additive described later.

When the base material layer 1 is formed of a resin, the base material layer 1 may be, for example, a resin film formed of a resin or a resin film applied to the base material layer 1. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferable. Examples of the stretching method for forming the biaxially stretched film include a sequential biaxial stretching method, an inflation method, and a simultaneous biaxial stretching method. Examples of the method for applying the resin include a roll coating method, a gravure coating method, and an extrusion coating method.

Examples of the resin forming the base material layer 1 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, and phenol resin, and modified products of these resins. Further, the resin forming the base material layer 1 may be a copolymer of these resins, or may be a modified product of the copolymer. Further, it may be a mixture of these resins.

Among these, preferable examples of the resin forming the base material layer 1 include polyester and polyamide.

Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester. Further, examples of the copolymerized polyester include a copolymerized polyester containing ethylene terephthalate as a repeating unit. Specifically, a copolymer polyester (hereinafter abbreviated after polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / terephthalate /), which polymerizes with ethylene isophthalate using ethylene terephthalate as a repeating unit as a main component. (Sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decandicarboxylate) and the like. These polyesters may be used alone or in combination of two or more.

Further, as the polyamide, specifically, an aliphatic polyamide such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, a copolymer of nylon 6 and nylon 66; terephthalic acid and / or isophthalic acid. Hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamide such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I stands for isophthalic acid, T stands for terephthalic acid), polyamide MXD6 (polymethaki) containing the derived structural units. Polyamide containing aromatics such as silylene adipamide); Alicyclic polyamide such as polyamide PACM6 (polybis (4-aminocyclohexyl) methaneadipamide); Further, lactam component and isocyanate component such as 4,4'-diphenylmethane-diisocyanate Examples thereof include a copolymerized polyamide, a polyesteramide copolymer or a polyether esteramide copolymer which is a copolymer of a copolymerized polyamide and a polyester or a polyalkylene ether glycol; and a polyamide such as these copolymers. These polyamides may be used alone or in combination of two or more.

The base material layer 1 preferably contains at least one of a polyester film, a polyamide film, and a polyolefin film, and preferably contains at least one of a stretched polyester film, a stretched polypropylene film, and a stretched polyolefin film. It is more preferable to contain at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film and a stretched polypropylene film, and a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film and a biaxially stretched nylon film. , It is more preferable to contain at least one of the biaxially stretched polypropylene films.

The base material layer 1 may be a single layer or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminated body in which a resin film is laminated with an adhesive or the like, or the resin is co-extruded to form two or more layers. It may be a laminated body of the resin film. Further, the laminated body of the resin film obtained by co-extruding the resin into two or more layers may be used as the base material layer 1 without being stretched, or may be uniaxially stretched or biaxially stretched as the base material layer 1.

Specific examples of the laminate of two or more layers of resin film in the base material layer 1 include a laminate of a polyester film and a nylon film, a laminate of two or more layers of nylon film, and a laminate of two or more layers of polyester film. And the like, preferably, a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more layers of stretched nylon film, and a laminate of two or more layers of stretched polyester film are preferable. For example, when the base material layer 1 is a laminate of two layers of resin film, a laminate of polyester resin film and polyester resin film, a laminate of polyamide resin film and polyamide resin film, or a laminate of polyester resin film and polyamide resin film. A laminate is preferable, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferable. Further, since the polyester resin is difficult to discolor when the electrolytic solution adheres to the surface, for example, when the base material layer 1 is a laminate of two or more resin films, the polyester resin film is the base material layer 1. It is preferably located in the outermost layer.

When the base material layer 1 is a laminated body of two or more layers of resin films, the two or more layers of resin films may be laminated via an adhesive. Preferred adhesives include those similar to the adhesives exemplified in the adhesive layer 2 described later. The method of laminating two or more layers of resin films is not particularly limited, and known methods can be adopted. Examples thereof include a dry laminating method, a sandwich laminating method, an extrusion laminating method, and a thermal laminating method, and a dry laminating method is preferable. The laminating method can be mentioned. When laminating by the dry laminating method, it is preferable to use a polyurethane adhesive as the adhesive. At this time, the thickness of the adhesive is, for example, about 2 to 5 μm. Further, an anchor coat layer may be formed on the resin film and laminated. Examples of the anchor coat layer include the same adhesives as those exemplified in the adhesive layer 2 described later. At this time, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

Further, even if additives such as a lubricant, a flame retardant, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent are present on at least one of the surface and the inside of the base material layer 1. Good. Only one type of additive may be used, or two or more types may be mixed and used.

In the present invention, from the viewpoint of improving the moldability of the packaging material for the power storage device, it is preferable that the lubricant is present on the surface of the base material layer 1. The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, bechenic acid amide, hydroxystearic acid amide and the like. Specific examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucate amide and the like. Further, specific examples of methylolamide include methylolstearic acid amide. Specific examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide, and hexamethylene bisstearate. Examples thereof include acid amides, hexamethylene bisbechenic acid amides, hexamethylene hydroxystearic acid amides, N, N'-distearyl adipate amides, and N, N'-distealyl sebasic acid amides. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N, N'-diorail adipate amide, and N, N'-diorail sebacic acid amide. And so on. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate and the like. Specific examples of the aromatic bisamide include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N, N'-distearyl isophthalic acid amide. One type of lubricant may be used alone, or two or more types may be used in combination.

If a lubricant on the surface of the base material layer 1 is present, as it is its abundance is not particularly limited, preferably about 3 mg / m ² or more, more preferably 4~15mg / m ² approximately, more preferably 5~14mg / M ² is mentioned.

The lubricant existing on the surface of the base material layer 1 may be one in which the lubricant contained in the resin constituting the base material layer 1 is exuded, or one in which the lubricant is applied to the surface of the base material layer 1. You may.

The thickness of the base material layer 1 is not particularly limited as long as it functions as a base material, and examples thereof include about 3 to 50 μm, preferably about 10 to 35 μm. When the base material layer 1 is a laminate of two or more resin films, the thickness of the resin films constituting each layer is preferably about 2 to 25 μm, respectively.

In the present invention, it is preferable to select a base material through which the wavelength of the laser light is easily transmitted as the base material layer 1. When the laser light used for image formation is, for example, a laser light having a wavelength of 1067 nm, it is more preferable to select the base material layer 1 having a light transmittance of 80% or more at 1067 nm. As such a base material layer 1, a polyamide film, a polyester film, or the like is preferable. The light transmittance of the base material layer 1 can be measured with, for example, an ultraviolet-visible spectrophotometer (UV-1900) manufactured by Shimadzu Corporation.

[Adhesive layer 2]
In the packaging material 10 for a power storage device of the present invention, the adhesive layer 2 is a layer that firmly adheres the base material layer 1 and the barrier layer 3 and can form an image by irradiating the adhesive layer 2 with a laser beam. is there. The adhesive layer 2 is provided between the base material layer 1 and the barrier layer 3 and is in contact with the barrier layer 3. The adhesive layer 2 may or may not be in contact with the base material layer 1. For example, an adhesive layer containing no material that enables image formation may exist between the base material layer 1 and the adhesive layer 2. The adhesion between the base material layer 1 and the barrier layer 3 via the adhesive layer 2 is improved, and the deterioration of the base material layer 1 due to image formation using the laser light is not required to increase the output of the laser light. From the viewpoint of suppressing, it is preferable that the surface is in contact with the base material layer 1.

In the packaging material 10 for a power storage device of the present invention, the adhesive layer 2 is a layer capable of forming an image by irradiating a laser beam, and an image may be formed on the adhesive layer 2 or an adhesive. An image may not be formed on the layer 2. Even when an image is not formed on the adhesive layer 2 of the packaging material 10 for a power storage device, an image can be formed on the adhesive layer 2 by irradiating the adhesive layer 2 with a laser beam. In the packaging material 10 for a power storage device of the present invention, it is visually recognized that an image is formed by changing the color and brightness of the portion irradiated with the laser beam by the irradiation of the laser beam. That is, in the power storage device, the image formed on the outside is visually confirmed.

The adhesive layer 2 is formed of an adhesive containing a material capable of forming an image on the packaging material 10 for a power storage device by irradiation with a laser beam and an adhesive component capable of adhering the base material layer 1 and the barrier layer 3 to each other. To.

As a material capable of forming an image by irradiation with laser light, conventionally known materials can be used, and examples thereof include bismuth compounds and black pigments. In the present invention, it is preferable to use a coloring material that develops color by irradiation with laser light as the material.

A bismuth-based compound is preferably used as a color-developing material that preferably develops a color by irradiation with a laser beam.

The bismuth-based compound is not particularly limited, and examples thereof include an organic salt of bismuth and / or an inorganic salt of bismuth. Specifically, for example, bismuth oxide; bismuth nitrate such as bismuth nitrate and bismuth oxynitrate; bismuth halide such as bismuth chloride; bismuth oxychloride, bismuth sulfate, bismuth acetate, bismuth citrate, bismuth hydroxide. , Bismuth titanate, bismuth hypocarbonate and the like are preferable as color-developing materials for developing color by low-power laser light. Among them, bismuth hydroxide, bismuth oxide, bismuth subcarbonate, and bismuth nitrate are particularly preferably used. As the bismuth compound, only one kind may be used, or two or more kinds may be mixed and used.

When a bismas-based compound is used in the adhesive layer 2, the content of the bismas-based compound contained in the adhesive layer 2 is not particularly limited, but the adhesive layer 2 contains a material capable of forming an image. Despite this, high adhesion between the base material layer 1 and the barrier layer 3 via the adhesive layer 2 is exhibited, and deterioration of each layer such as the base material layer 1 due to irradiation with laser light is minimized. From the viewpoint of suppressing to, the lower limit is preferably about 0.1% by mass or more, more preferably about 1% by mass or more, further preferably about 2% by mass or more, and the upper limit is preferably about 50% by mass or less. , More preferably about 30% by mass or less, still more preferably about 25% by mass or less, and preferred ranges are about 0.1 to 50% by mass, about 0.1 to 30% by mass, and 0.1 to 25% by mass. %, About 1 to 50% by mass, about 1 to 30% by mass, about 1 to 25% by mass, about 2 to 50% by mass, about 2 to 30% by mass, and about 2 to 25% by mass.

Further, in the present invention, it is preferable to use a black pigment such as carbon black in combination with a bismuth compound as a material that enables image formation by irradiation with laser light. By using the bismuth-based compound and the black pigment in combination, an image can be suitably formed on the adhesive layer 2 by irradiation with a laser beam, so that the deterioration of the base material layer 1 due to the image formation using the laser beam is deteriorated. It is suitably suppressed, and the adhesion between the base material layer and the barrier layer can be enhanced. Further, by using the black pigment, it is possible to form an image of another color (for example, white) on the adhesive layer 2 colored in a black color by irradiating the adhesive layer 2 with a laser beam. When a bismuth compound and a black pigment are used in combination, it is considered that the sublimation rate of the black pigment is increased by the laser light absorption of bismuth, and as a result, an image can be formed by a lower energy laser light.

When a black pigment is used in the adhesive layer 2, the total content of the materials capable of forming an image by irradiation with laser light is not particularly limited, but the adhesive layer 2 contains a material capable of forming an image. Despite this, high adhesion between the base material layer 1 and the barrier layer 3 is exhibited, the adhesive layer 2 is black, and each layer such as the base material layer is deteriorated by irradiation with laser light. From the viewpoint of minimizing, the lower limit is preferably about 0.1% by mass or more, more preferably about 1% by mass or more, still more preferably about 2% by mass or more, and the upper limit is preferably about 50% by mass. % Or less, more preferably about 30% by mass or less, still more preferably about 25% by mass or less, and preferred ranges are about 0.1 to 50% by mass, about 0.1 to 30% by mass, and 0.1 to 1. Examples thereof include about 25% by mass, about 1 to 50% by mass, about 1 to 30% by mass, about 1 to 25% by mass, about 2 to 50% by mass, about 2 to 30% by mass, and about 2 to 25% by mass.

In the adhesive layer 2, as a particularly preferable embodiment of the material capable of forming an image by irradiating the laser beam, only bismuth compounds (particularly bismuth oxide) are used as the material capable of forming an image by irradiating the laser beam. Examples thereof include those containing about 30% by mass. Further, when an image of another color (for example, white) is formed by irradiating the adhesive layer 2 colored in black with a laser beam, the image can be formed by irradiating the laser beam. Examples of the material to be used include those containing about 1 to 10% by mass of a bismuth-based compound (particularly bismuth oxide) and about 10 to 20% by mass of a black pigment (particularly carbon black).

Further, when the bismuth-based compound and the black pigment are used in combination in the adhesive layer 2, the base material layer via the adhesive layer 2 is interposed even though the adhesive layer 2 contains a material capable of forming an image. Adhesion from the viewpoint of exhibiting high adhesion between 1 and the barrier layer 3 and suppressing deterioration of the base material layer 1 due to image formation using laser light without having to increase the output of laser light. The mass ratio of the bismuth-based compound contained in the agent layer 2 to the black pigment (bismuth-based compound: black pigment) is preferably about 1: 0.5 to 15, more preferably about 1: 0.8 to 15. More preferably, it is about 1: 1 to 8.

Further, as another material that can form an image by irradiation with laser light, colorants such as dyes and pigments, clays and the like can be used. Specifically, metal compounds such as yellow iron oxide, inorganic lead compounds, manganese violet, cobalt violet, metals composed of mercury, cobalt, copper, nickel, etc., pearl luster pigments, silicon compounds, mica, kaolins, silica sand, etc. Polymorphic soil, talc, titanium oxide-coated mica, tin dioxide-coated mica, antimon-coated mica, tin + antimon-coated mica, tin + antimon + titanium oxide-coated mica and the like can also be used.

The total content of the materials capable of forming an image by irradiation with laser light in the adhesive layer 2 is not particularly limited, but the adhesive layer 2 is adhered even though the adhesive layer 2 contains a material capable of forming an image. From the viewpoint of exhibiting high adhesion between the base material layer 1 and the barrier layer 3 via the agent layer 2 and further minimizing the deterioration of each layer such as the base material layer 1 due to irradiation with laser light. The lower limit is preferably about 0.1% by mass or more, more preferably about 1% by mass or more, further preferably about 2% by mass or more, and the upper limit is preferably about 50% by mass or less, more preferably about. It is 30% by mass or less, more preferably about 25% by mass or less, and the preferred ranges are about 0.1 to 50% by mass, about 0.1 to 30% by mass, about 0.1 to 25% by mass, and 1 to 1. Examples thereof include about 50% by mass, about 1 to 30% by mass, about 1 to 25% by mass, about 2 to 50% by mass, about 2 to 30% by mass, and about 2 to 25% by mass.

Further, the adhesive layer 2 may contain one or more inorganic compounds for improving the color development efficiency. Examples of such inorganic compounds include metal oxides such as titanium oxide, magnesium oxide, zinc oxide, aluminum oxide, silicon oxide, nickel oxide, tin oxide, neodymium oxide, mica, zeolite, kaolinite, copper compounds, and molybdenum. Examples thereof include system compounds, copper / molybdenum composite oxides, copper / tungsten compounds, and metal salts.

As the copper-based compound, for example, organic copper acids such as copper oxide, copper halide, formic acid, citric acid, salicylic acid, lauric acid, oxalic acid and maleic acid, and inorganic copper such as copper phosphate and copper hydroxyphosphate are suitable. Can be used for.

As the molybdenum-based compound, molybdenum, molybdenum dioxide, molybdenum trioxide, molybdenum chloride, and metal molybdate (metals: K, Zn, Ca, Ni, bismuth, Mg, etc.) can be preferably used.

As the metal salt, a salt of an acid such as sulfuric acid, nitric acid, oxalic acid or carbonic acid and a metal such as barium, cobalt, magnesium, nickel or iron can be used.

When the adhesive layer 2 contains an inorganic compound, the content of the inorganic compound in the adhesive layer 2 is preferably about 5 to 65% by mass.

The adhesive component contained in the adhesive forming the adhesive layer 2 may be a two-component curing type or a one-component curing type. Further, the adhesive mechanism of the adhesive component is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a thermal pressure type and the like.

Specific examples of the adhesive component that can be used to form the adhesive layer 2 include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; polyether; polyurethane. Epoxy resin; Phenolic resin resin; Polyethylene such as nylon 6, nylon 66, nylon 12, copolymerized polyamide; polyolefin resin such as polyolefin, acid-modified polyolefin, metal-modified polyolefin, polyvinyl acetate resin; Cellulosic resin (Meta) acrylic resin; polyimide; amino resin such as urea resin and melamine resin; silicone resin; rubber and resin such as chloroprene rubber, nitrile rubber and styrene-butadiene rubber. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, polyurethane is preferable.

The content of the adhesive component in the adhesive layer 2 is not particularly limited, but the base material layer 1 is interposed through the adhesive layer 2 even though the adhesive layer 2 contains a material capable of forming an image. Regarding the lower limit from the viewpoint of exhibiting high adhesion between the and the barrier layer 3 and suppressing deterioration of the base material layer 1 due to image formation using the laser beam without having to increase the output of the laser beam. Is preferably about 50% by mass or more, more preferably about 60% by mass or more, further preferably about 65% by mass or more, still more preferably about 70% by mass or more, still more preferably about 75% by mass or more, and the upper limit. Is preferably about 99.9% by mass or less, more preferably about 99% by mass or less, still more preferably about 98% by mass or less, and preferably in the range of about 50 to 99.9% by mass and 50 to 99% by mass. %, 50 to 98% by mass, 60 to 99.9% by mass, 60 to 99% by mass, 60 to 98% by mass, 65 to 99.9% by mass, 65 to 99% by mass, 65 About 98% by mass, about 70 to 99.9% by mass, about 70 to 99% by mass, about 70 to 98% by mass, about 75 to 99.9% by mass, about 75 to 99% by mass, about 75 to 98% by mass. The degree can be mentioned. The content of the adhesive component of the adhesive layer 2 is various known such as cross-sectional observation of the adhesive layer 2 (for example, cross-sectional observation by a scanning electron microscope, energy dispersive X-ray analysis, infrared absorption spectroscopy, etc.). It can be measured by the analysis method). The content of the material that can form an image by irradiating the adhesive layer 2 with a laser beam can also be measured by various known analysis methods in the same manner.

In the packaging material for a power storage device of the present invention, the adhesive strength between the base material layer 1 and the barrier layer 3 is preferably 3N / 15 mm or more, more preferably 4N / 15 mm or more, still more preferably 5N / 15 mm or more. Can be mentioned. The upper limit of the adhesive strength is, for example, 6N / 15 mm or less. The method for measuring the adhesive strength is as follows.

(Measurement method of adhesive strength)
A test sample is prepared by cutting out a packaging material for a power storage device (those not irradiated with laser light) into a size of 100 mm in length and 15 mm in width. Next, using a tensile tester (for example, an autograph manufactured by Shimadzu Corporation), the base material layer and the barrier layer of each test sample were subjected to the conditions of a tensile speed of 200 mm / min, a peeling angle of 180 °, and a chuck distance of 50 mm. The peeling strength (N / 15 mm) is measured by peeling the gap in the length direction. When a test sample of the above size cannot be prepared due to the small size of the packaging material for the power storage device, the measurement is performed in a measurable size, and the adhesive strength is calculated by converting to a width of 15 mm.

The thickness of the adhesive layer 2 is high between the base material layer 1 and the barrier layer 3 via the adhesive layer 2 even though the adhesive layer 2 contains a material that enables image formation. From the viewpoint of exhibiting adhesiveness, not needing to increase the output of the laser beam, and suppressing deterioration of the base material layer 1 due to image formation using the laser beam, the lower limit is preferably about 1 μm or more. The upper limit is preferably about 2 μm or more, and the upper limit is preferably about 10 μm or less, more preferably about 5 μm or less, and the preferred ranges are about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and 2 It is about 5 μm.

(Image formation by laser light)
The image formation of the adhesive layer 2 by the laser beam is performed by YAG (yttrium (Y), aluminum (A), garnet (G)) laser beam (wavelength = 1.064 μm), YVO ₄ (yttrium vanadate) laser beam (wavelength). = 1.064 μm), preferably using a fiber laser beam (for example, wavelength = 1090 nm) or the like. These lasers have a property of transmitting through a transparent body, and by utilizing this property, it is possible to suppress the generation of smoke or the like during image formation, and to adjust the color development density and the influence on each layer. As a result, even if the image is formed by the laser beam, an extremely clear image without holes or the like can be formed.

In the packaging material for a power storage device of the present invention or the power storage device of the present invention described later, by irradiating these laser beams from the base material layer 1 side, deterioration of each layer such as the base material layer can be achieved with low output. An image can be suitably formed on the adhesive layer 2 while keeping it to a minimum.

As the pulse conditions of the laser light, for example, a pulse with a fiber laser machine (for example, LP-Z250 manufactured by Panasonic Industrial Devices SUNX Co., Ltd., wavelength 1060 nm) has a scan speed of 300 to 4000 mm / s, more preferably 1500 to 4000 mm / s. The condition is used. By forming an image under these conditions, high-speed image formation is possible and a clear image can be obtained.

The image includes characters, numbers, symbols, patterns, barcodes, patterns, logos, etc., and the shape of the image is not limited to these. In the process of forming an image by laser light, a clear image, for example, clear characters can be formed even if the average output of the laser is set low or the scan speed is set high.

The diameter of the discoloration region formed by the spot irradiation of the laser beam is preferably about 40 μm to 1 mm, more preferably about 200 to 700 μm. A clear image can be obtained in this discoloration range. If the diameter of the discoloration area is smaller than this, image loss and line width narrowing occur, resulting in poor visibility. On the contrary, if it is larger than this, the image is crushed, which is not preferable. The diameter of the dots formed by spot irradiation of the laser beam is, for example, about 80 to 500 μm.

[Barrier layer 3]
In the packaging material for a power storage device, the barrier layer 3 is at least a layer that suppresses the infiltration of water.

Examples of the barrier layer 3 include a metal foil having a barrier property, a thin-film deposition film, a resin layer, and the like. Examples of the vapor deposition film include a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, and the like, and examples of the resin layer include polyvinylidene chloride. Further, examples of the barrier layer 3 include a resin film provided with at least one of these vapor-deposited films and a resin layer. A plurality of barrier layers 3 may be provided. The barrier layer 3 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include an aluminum alloy, stainless steel, titanium steel, and the like, and when used as a metal foil, it may contain at least one of an aluminum alloy foil and a stainless steel foil. preferable.

From the viewpoint of improving the moldability of the packaging material for the power storage device, the aluminum alloy foil is more preferably a soft aluminum alloy foil composed of, for example, an annealed aluminum alloy, and the viewpoint of further improving the moldability. Therefore, it is preferable that the aluminum alloy foil contains iron. In the aluminum alloy foil containing iron (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, a packaging material for a power storage device having more excellent moldability can be obtained. When the iron content is 9.0% by mass or less, a packaging material for a power storage device having more excellent flexibility can be obtained. Examples of the soft aluminum alloy foil include an aluminum alloy having a composition defined by JIS H4160: 1994 A8021H-O, JIS H4160: 1994 A8079H-O, JIS H4000: 2014 A8021P-O, or JIS H4000: 2014 A8079P-O. Foil is mentioned.

Examples of the stainless steel foil include austenite-based, ferrite-based, austenite-ferritic-based, martensitic-based, and precipitation-hardened stainless steel foils. Further, from the viewpoint of providing a packaging material for a power storage device having excellent moldability, the stainless steel foil is preferably made of austenitic stainless steel.

Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferable.

In the case of a metal foil, the thickness of the barrier layer 3 may be at least a function as a barrier layer for suppressing the infiltration of water, and is, for example, about 9 to 200 μm. The thickness of the barrier layer 3 is, for example, preferably about 85 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, particularly preferably about 35 μm or less, and the lower limit is preferably about about. 10 μm or more, more preferably about 20 μm or more, more preferably about 25 μm or more, and preferable ranges of the thickness are about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, and about 20 to 20. Examples thereof include about 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 3 is made of an aluminum alloy foil, the above range is particularly preferable. Further, in particular, when the barrier layer 3 is made of stainless steel foil, the upper limit of the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less. More preferably, it is about 30 μm or less, particularly preferably about 25 μm or less, and the lower limit is preferably about 10 μm or more, more preferably about 15 μm or more, and the preferred thickness range is about 10 to 60 μm, 10 Examples thereof include about 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

When the barrier layer 3 is a metal foil, it is preferable that a corrosion-resistant film is provided at least on the surface opposite to the base material layer in order to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion-resistant film on both sides. Here, the corrosion-resistant film means, for example, a hot water transformation treatment such as boehmite treatment, a chemical conversion treatment, an anodization treatment, and a corrosion prevention treatment of applying a coating agent on the surface of the barrier layer, and the barrier layer is subjected to corrosion resistance. A thin film having properties (for example, acid resistance, alkali resistance, etc.). Specifically, the corrosion-resistant film means a film for improving the acid resistance of the barrier layer (acid-resistant film), a film for improving the alkali resistance of the barrier layer (alkali-resistant film), and the like. As the treatment for forming the corrosion-resistant film, one type may be performed, or two or more types may be combined. Further, among these treatments, the hydrothermal modification treatment and the anodizing treatment are treatments in which the surface of the metal foil is dissolved by a treatment agent to form a metal compound having excellent corrosion resistance. Note that these processes may be included in the definition of chemical conversion process. When the barrier layer 3 has a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

Various corrosion-resistant films formed by chemical conversion treatment are known, and mainly, at least one of phosphate, chromate, fluoride, triazinethiol compound, and rare earth oxide. Examples include a corrosion-resistant film containing. As the rare earth oxide, a cerium compound is preferable, and cerium oxide is particularly preferable. Examples of the chemical conversion treatment using a phosphate or a chromate include a chromium acid chromate treatment, a phosphoric acid chromate treatment, a phosphoric acid-chromate treatment, a chromium salt treatment, and the like, and chromium used in these treatments. Examples of the compound include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium dichromate, acetylacetate chromate, chromium chloride, and chromium potassium sulfate. Further, examples of the phosphorus compound used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid and the like. Further, examples of the chromate treatment include etching chromate treatment, electrolytic chromate treatment, and coating type chromate treatment, and coating type chromate treatment is preferable. In this coating type chromate treatment, at least the inner layer side surface of the barrier layer (for example, aluminum alloy foil) is first known as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activation method and the like. Degreasing is performed by the treatment method, and then metal phosphates such as Cr phosphate (chromium) salt, Ti (titanium) phosphate, Zr (zyroxide) salt, and Zn (zinc) phosphate are applied to the degreased surface. A treatment solution (aqueous solution) containing a salt and a mixture of these metal salts as a main component, or a treatment solution (aqueous solution) containing a mixture of a phosphate non-metal salt and these non-metal salts as a main component, or these. This is a treatment in which a treatment liquid (aqueous solution) composed of a mixture of a synthetic resin and the like is coated by a well-known coating method such as a roll coating method, a gravure printing method, or a dipping method, and dried. Further, examples of the resin component used at this time include water-soluble polymers such as phenol and polyacrylic acid, and an amination phenol polymer having a repeating unit represented by the following general formulas (1) to (4) is used. Examples include the chromate treatment that was used. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. May be good.

In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. Further, R ¹ and R ² represent a hydroxy group, an alkyl group, or a hydroxyalkyl group, respectively, which are the same or different. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group. Examples thereof include linear or branched alkyl groups having 1 to 4 carbon atoms such as tert-butyl groups. Examples of the hydroxyalkyl groups represented by X, R ¹ and R ² include hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group and 3-. A linear or branched chain having 1 to 4 carbon atoms in which one hydroxy group such as a hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, or a 4-hydroxybutyl group is substituted. Alkyl groups can be mentioned. In the general formulas (1) to (4), the alkyl group and the hydroxyalkyl group represented by X, R ¹ and R ² may be the same or different, respectively. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having the repeating unit represented by the general formulas (1) to (4) is preferably, for example, about 5 to 1,000,000, and preferably about 1,000 to 20,000. More preferred. The amination phenol polymer, for example, polycondenses a phenol compound or a naphthol compound with formaldehyde to produce a polymer composed of repeating units represented by the above general formula (I) or general formula (III), and then formsaldehyde. It is produced by introducing a water-soluble functional group (-CH ₂ NR ¹ R ² ) into the polymer obtained above using amine (R ¹ R ² NH). The aminated phenol polymer is used alone or in combination of two or more.

The corrosion-resistant film is formed by preventing delamination between the barrier layer (for example, aluminum alloy foil) and the base material layer during molding of the packaging material for a power storage device, and by hydrogen fluoride generated by the reaction between the electrolyte and water. , Melting and corrosion of the barrier layer surface, especially when the barrier layer is an aluminum alloy foil, it prevents the aluminum oxide existing on the barrier layer surface from melting and corroding, and the adhesiveness (wetness) of the barrier layer surface. The effect of preventing delamination between the base material layer and the barrier layer during heat sealing and preventing delamination between the base material layer and the barrier layer during molding is shown.

As another example of the corrosion resistant film, it is formed by a coating type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of rare earth element oxide sol, anionic polymer, and cationic polymer is applied. The thin film to be used is mentioned. The coating agent may further contain phosphoric acid or phosphate, a cross-linking agent for cross-linking the polymer. In the rare earth element oxide sol, fine particles of the rare earth element oxide (for example, particles having an average particle size of 100 nm or less) are dispersed in a liquid dispersion medium. Examples of the rare earth element oxide include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide, and cerium oxide is preferable from the viewpoint of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant film may be used alone or in combination of two or more. As the liquid dispersion medium of the rare earth element oxide sol, for example, various solvents such as water, alcohol solvent, hydrocarbon solvent, ketone solvent, ester solvent, ether solvent and the like can be used, and water is preferable. Examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of polyethyleneimine and a polymer having a carboxylic acid, a primary amine graft acrylic resin obtained by graft-polymerizing a primary amine on an acrylic main skeleton, polyallylamine or a derivative thereof. , Amination phenol and the like are preferable. The anionic polymer is preferably a poly (meth) acrylic acid or a salt thereof, or a copolymer containing (meth) acrylic acid or a salt thereof as a main component. Further, it is preferable that the cross-linking agent is at least one selected from the group consisting of a compound having a functional group of any of an isocyanate group, a glycidyl group, a carboxyl group and an oxazoline group and a silane coupling agent. Further, it is preferable that the phosphoric acid or phosphate is condensed phosphoric acid or condensed phosphate.

As an example of the corrosion-resistant film, a film in which fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide and barium sulfate are dispersed in phosphoric acid is applied to the surface of the barrier layer, and 150 Examples thereof include those formed by performing a baking treatment at ° C or higher.

If necessary, the corrosion-resistant film may have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated. Examples of the cationic polymer and the anionic polymer include those described above.

The composition of the corrosion-resistant film can be analyzed by using, for example, a time-of-flight secondary ion mass spectrometry method.

The amount of the corrosion-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited, but for example, in the case of performing a coating type chromate treatment, a chromic acid compound per 1 m ² of the surface of the barrier layer 3 Is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of chromium, and the phosphorus compound is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of phosphorus, and an amination phenol polymer. Is preferably contained in a proportion of, for example, about 1.0 to 200 mg, preferably about 5.0 to 150 mg.

The thickness of the corrosion-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably 1 nm to 100 nm, from the viewpoint of the cohesive force of the film and the adhesion to the barrier layer and the thermosetting resin layer. The degree, more preferably about 1 nm to 50 nm. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope or a combination of observation with a transmission electron microscope and energy dispersion type X-ray spectroscopy or electron beam energy loss spectroscopy. The time-of-flight secondary ion mass spectrometry analysis of the composition of the corrosion resistant coating using, for example, secondary ion consisting Ce and P and O ^{_{(e.g., Ce 2 PO 4 +, CePO}} 4 - at least 1, such as species) or, for example, secondary ion of Cr and P and O (e.g., CrPO ₂ ^+, CrPO ₄ ^- peak derived from at least one), such as is detected.

In the chemical conversion treatment, a solution containing a compound used for forming a corrosion-resistant film is applied to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then the temperature of the barrier layer is applied. It is carried out by heating so that the temperature is about 70 to 200 ° C. Further, before the chemical conversion treatment is applied to the barrier layer, the barrier layer may be subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method or the like in advance. By performing the degreasing treatment in this way, it becomes possible to more efficiently perform the chemical conversion treatment on the surface of the barrier layer. Further, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for the degreasing treatment, it is possible to form not only the degreasing effect of the metal foil but also the immobile metal fluoride. In such cases, only degreasing treatment may be performed.

[Thermosetting resin layer 4]
In the packaging material for a power storage device of the present invention, the thermosetting resin layer 4 corresponds to the innermost layer, and the heat-sealing resin layers are heat-sealed to each other during assembly of the power storage device to seal the power storage device element. Is.

The resin component used in the heat-fusing resin layer 4 is not particularly limited as long as it can be heat-fused, and examples thereof include polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins. That is, the resin constituting the thermosetting resin layer 4 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The fact that the resin constituting the heat-sealing resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of the polyolefin include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and other polyethylene; homopolypropylene, polypropylene block copolymer (for example, propylene and ethylene block copolymer), and polypropylene. Polypropylene such as random copolymers of propylene and ethylene (eg, random copolymers of propylene and ethylene); ethylene-butene-propylene tarpolymers; and the like. Among these polyolefins, polyethylene and polypropylene are preferable.

The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, isoprene, and the like. Can be mentioned. Examples of the cyclic monomer which is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specific examples thereof include cyclic diene such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkene is preferable, and norbornene is more preferable.

The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of the polyolefin with an acid component. Examples of the acid component used for the modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

The acid-modified cyclic polyolefin means that a part of the monomer constituting the cyclic polyolefin is copolymerized in place of α, β-unsaturated carboxylic acid or its anhydride, or α, β-with respect to the cyclic polyolefin. It is a polymer obtained by block polymerization or graft polymerization of unsaturated carboxylic acid or its anhydride. The same applies to the cyclic polyolefins that are acid-modified. The acid component used for the modification is the same as that used for the modification of the polyolefin.

Among these resin components, acid-modified polyolefin is preferable; and acid-modified polypropylene is more preferable.

The thermosetting resin layer 4 may be formed by one kind of resin component alone, or may be formed by a blend polymer in which two or more kinds of resin components are combined. Further, the thermosetting resin layer 4 may be formed of only one layer, or may be formed of two or more layers with the same or different resin components.

In the present invention, from the viewpoint of improving the moldability of the packaging material for the power storage device, it is preferable that the lubricant is present on the surface of the thermosetting resin layer 4. Since the lubricant is present on the surface of the thermosetting resin layer 4 and the lubricant layer is formed, curling due to molding of the packaging material for the power storage device is suppressed, and the moldability of the packaging material for the power storage device is improved. Can be done. The lubricant is not particularly limited, and a known lubricant can be used. The lubricant may be used alone or in combination of two or more.

The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides and the like. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, bechenic acid amide, hydroxystearic acid amide and the like. Specific examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucate amide and the like. Further, specific examples of methylolamide include methylolstearic acid amide. Specific examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide, and hexamethylene bisstearate. Examples thereof include acid amides, hexamethylene bisbechenic acid amides, hexamethylene hydroxystearic acid amides, N, N'-distearyl adipate amides, and N, N'-distealyl sebasic acid amides. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N, N'-diorail adipate amide, and N, N'-diorail sebacic acid amide. And so on. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate and the like. Specific examples of the aromatic bisamide include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N, N'-distearyl isophthalic acid amide. One type of lubricant may be used alone, or two or more types may be used in combination.

The amount of the lubricant present on the surface of the thermosetting resin layer 4 is not particularly limited, and from the viewpoint of improving the moldability of the packaging material for the power storage device, it is preferably 10 in an environment of a temperature of 24 ° C. and a relative humidity of 60%. to 50 mg / m ² about, even more preferably include about 15~40mg / m ^2.

The thermosetting resin layer 4 may contain a lubricant. Further, the lubricant existing on the surface of the thermosetting resin layer 4 may be one obtained by exuding the lubricant contained in the resin constituting the thermosetting resin layer 4, or may be a thermosetting resin layer. The surface of No. 4 may be coated with a lubricant.

Further, the thickness of the thermosetting resin layer 4 can be set according to the presence or absence of the adhesive layer 5, the thickness of the adhesive layer 5, and the like, and is particularly effective as long as it exhibits the function as the thermosetting resin layer. Although not limited, the upper limit is, for example, about 100 μm or less, preferably about 85 μm or less, more preferably 60 μm or less, and the lower limit is, for example, about 15 μm or more, preferably 20 μm or more. Examples thereof include about 15 to 100 μm, about 15 to 85 μm, about 15 to 60 μm, about 20 to 100 μm, about 20 to 85 μm, and about 20 to 60 μm. In particular, for example, when the thickness of the adhesive layer 5 described later is 10 μm or more, the upper limit of the thickness of the thermosetting resin layer 4 is preferably about 85 μm or less, more preferably about 60 μm or less. The lower limit is, for example, about 15 μm or more, preferably 20 μm or more, and the preferable range is about 15 to 85 μm, about 15 to 60 μm, about 20 to 85 μm, and about 20 to 60 μm. Further, for example, when the thickness of the adhesive layer 5 described later is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the thermosetting resin layer 4 is preferably about 20 μm or more, more preferably. The size is about 35 to 85 μm.

[Adhesive layer 5]
In the packaging material for a power storage device of the present invention, the adhesive layer 5 is a layer provided as necessary between the barrier layer 3 and the thermosetting resin layer 4 in order to firmly bond them.

The adhesive layer 5 is formed of a resin capable of adhering the barrier layer 3 and the thermosetting resin layer 4 to each other. As the resin used for forming the adhesive layer 5, polyolefin-based resins such as the polyolefin, cyclic polyolefin, acid-modified polyolefin, and acid-modified cyclic polyolefin exemplified in the above-mentioned heat-sealing resin layer 4 can be preferably used. As the polyolefin-based resin, polypropylene-based resins such as polypropylene, cyclic polypropylene, acid-modified polypropylene, and acid-modified cyclic polypropylene can be preferably used. In this case, the thermosetting resin layer 4 and the adhesive layer 5 can be suitably formed by extrusion molding.

Further, as the resin used for forming the adhesive layer 5, the same resin as the adhesive exemplified in the adhesive layer 2 can be used.

From the viewpoint of excellent adhesion between the barrier layer 3 and the heat-sealing resin layer 4, the polyolefin-based resin is preferably polyolefin or acid-modified polyolefin, and particularly preferably polypropylene or acid-modified polypropylene. That is, the resin constituting the adhesive layer 5 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The fact that the resin constituting the adhesive layer 5 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

From the viewpoint of improving the adhesion between the barrier layer 3 (or the corrosion resistant film) and the thermosetting resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of polyolefin with an acid component such as carboxylic acid. Examples of the acid component used for the modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, or anhydrides thereof. The modified polyolefins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and other polyethylene; homopolypropylene, polypropylene block copolymers (for example, propylene and ethylene block copolymers), and polypropylene. Polypropylene such as random copolymers (eg, random copolymers of propylene and ethylene); ethylene-butene-propylene tarpolymers and the like. Among these polyolefins, polyethylene and polypropylene are preferable.

Among the acid-modified polyolefins in the adhesive layer 5, maleic anhydride-modified polyolefin and maleic anhydride-modified polypropylene are particularly preferable.

Further, from the viewpoint of making the packaging material for the energy storage device excellent in shape stability after molding while reducing the thickness of the packaging material for the energy storage device, the adhesive layer 5 is a resin composition containing an acid-modified polyolefin and a curing agent. It is more preferable that it is a cured product of. As the acid-modified polyolefin, the above-mentioned ones are preferably exemplified.

The adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. It is particularly preferable that the resin composition is a cured product containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. Further, the adhesive layer 5 preferably contains at least one selected from the group consisting of urethane resin, ester resin, and epoxy resin, and more preferably contains urethane resin and epoxy resin. As the ester resin, for example, an amide ester resin is preferable. The amide ester resin is generally produced by the reaction of a carboxyl group and an oxazoline group. The adhesive layer 5 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. When an unreacted substance of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remains in the adhesive layer 5, the presence of the unreacted substance is determined by, for example, infrared spectroscopy. It can be confirmed by a method selected from Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

Further, from the viewpoint of further enhancing the adhesion between the barrier layer 3 (or the corrosion resistant film), the thermosetting resin layer 4, and the adhesive layer 5, the adhesive layer 5 has an oxygen atom, a heterocycle, and a C = N bond. It is preferable that the resin composition contains a curing agent having at least one selected from the group consisting of C—O—C bonds. Examples of the curing agent having a heterocycle include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C = N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C—O—C bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and a urethane resin. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents is, for example, gas chromatograph mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF). -SIMS), X-ray photoelectron spectroscopy (XPS) and other methods can be used for confirmation.

The compound having an isocyanate group is not particularly limited, but a polyfunctional isocyanate compound is preferable from the viewpoint of effectively enhancing the adhesion between the barrier layer 3 (or the corrosion resistant film) and the adhesive layer 5. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include pentandiisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI), which are polymerized or nurate. Examples thereof include chemical compounds, mixtures thereof, and copolymers with other polymers.

The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. More preferably in the range.

The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. In addition, examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. It is more preferable to be in. Thereby, the adhesion between the barrier layer 3 (or the corrosion resistant film) and the adhesive layer 5 can be effectively enhanced.

The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by an epoxy group existing in the molecule, and a known epoxy resin can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, and even more preferably about 200 to 800. In the present invention, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) measured under the condition that polystyrene is used as a standard sample.

Specific examples of the epoxy resin include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolak glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether and the like. One type of epoxy resin may be used alone, or two or more types may be used in combination.

The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Is more preferable. Thereby, the adhesion between the barrier layer 3 (or the corrosion resistant film) and the adhesive layer 5 can be effectively enhanced.

In the present invention, the adhesive layer 5 is cured of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin. In the case of a product, the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the epoxy resin each function as a curing agent.

The thickness of the adhesive layer 5 is preferably about 30 μm or less, more preferably about 20 μm or less, still more preferably about 5 μm or less, and the lower limit is about 0.1 μm or more and about 0.5 μm or more. The thickness range is preferably about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, and about 0.5 to. The size is about 5 μm.

The carbodiimide-based curing agent is not particularly limited as long as it is a compound having at least one carbodiimide group (-N = C = N-). As the carbodiimide-based curing agent, a polycarbodiimide compound having at least two or more carbodiimide groups is preferable.

The curing agent may be composed of two or more kinds of compounds from the viewpoint of enhancing the adhesion between the barrier layer 3 by the adhesive layer 5 and the thermosetting resin layer 4.

The content of the curing agent in the resin composition forming the adhesive layer 5 is preferably in the range of about 0.1 to 50% by mass, more preferably in the range of about 0.1 to 30% by mass. It is more preferably in the range of about 0.1 to 10% by mass.

Further, the adhesive layer 5 can be suitably formed by using, for example, an adhesive. Examples of the adhesive include a non-crystalline polyolefin resin (A) having a carboxyl group, a polyfunctional isocyanate compound (B), and a tertiary amine having no functional group that reacts with the polyfunctional isocyanate compound (B). C) is contained, and the polyfunctional isocyanate compound (B) is contained in a range in which the amount of isocyanate groups is 0.3 to 10 mol with respect to a total of 1 mol of carboxyl groups, with respect to a total of 1 mol of carboxyl groups. Examples thereof include those formed from an adhesive composition containing a tertiary amine (C) in a range of 1 to 10 mol. Further, as the adhesive, the styrene-based thermoplastic elastomer (A), the tackifier (B), and the polyisocyanate (C) are contained, and the styrene-based thermoplastic elastomer (A) and the tackifier (B) are contained. The styrene-based thermoplastic elastomer (A) is contained in an amount of 20 to 90% by weight and the pressure-sensitive adhesive (B) is contained in an amount of 10 to 80% by weight, and the styrene-based thermoplastic elastomer (A) is contained in 100% by weight. , 0.003 to 0.04 mmol / g of active hydrogen derived from an amino group or hydroxyl group, and the pressure-sensitive adhesive (B) with respect to 1 mol of the active hydrogen derived from the styrene-based thermoplastic elastomer (A). The amount of active hydrogen derived from the functional group is 0 to 15 mol, and the polyisocyanate (C) is the sum of the active hydrogen derived from the styrene-based thermoplastic elastomer (A) and the active hydrogen derived from the tackifier (B). Examples thereof include those formed by an adhesive composition comprising an isocyanate group contained in a range of 3 to 150 mol with respect to 1 mol.

Regarding the thickness of the adhesive layer 5, the lower limit is preferably about 2 μm or more, about 10 μm or more, about 13 μm or more, about 15 μm or more, about 20 μm or more, and the upper limit is about 50 μm or less and about 45 μm or less. Preferred ranges include about 2 to 50 μm, about 10 to 50 μm, about 13 to 50 μm, about 15 to 50 μm, about 20 to 50 μm, about 2 to 45 μm, about 10 to 45 μm, about 13 to 45 μm, and about 15 to 15. About 45 μm and about 20 to 45 μm can be mentioned. As the adhesive layer 5, it is preferable to use a polyolefin resin such as the polyolefin resin and the acid-modified polyolefin resin exemplified in the thermosetting resin layer 4, and in this case, the thickness of the adhesive layer is about about the lower limit. It is preferably 10 μm or more and about 20 μm or more, and the upper limit is particularly preferably about 50 μm or less. Further, the adhesive exemplified in the adhesive layer 2 can also be used, and in this case, the thickness of the adhesive layer is preferably about 2 to 10 μm and about 2 to 5 μm. Further, in the case of a cured product of the acid-modified polyolefin and the curing agent, it is preferably about 30 μm or less, more preferably about 0.1 to 20 μm, and further preferably about 0.5 to 5 μm. In the case of the adhesive layer formed by the above-mentioned adhesive composition, the thickness after drying and curing is about 1 to 30 g / m ² . When the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed by applying the resin composition and curing it by heating or the like.

[Surface coating layer 6]
In the packaging material for a power storage device of the present invention, for the purpose of improving designability, electrolytic solution resistance, scratch resistance, moldability, etc., if necessary, on the base material layer 1 (barrier of the base material layer 1). A surface coating layer 6 may be provided on the side opposite to the layer 3), if necessary. The surface coating layer 6 is a layer located on the outermost layer when the power storage device is assembled.

The surface coating layer 6 can be formed of, for example, polyvinylidene chloride, a polyester resin, a urethane resin, an acrylic resin, an epoxy resin, or the like. Among these, the surface coating layer 6 is preferably formed of a two-component curable resin. Examples of the two-component curable resin forming the surface coating layer 6 include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Further, an additive may be blended in the surface coating layer 6. The additive to be added may function as, for example, a matting agent, and the surface coating layer may function as a matting layer. For example, when the surface coating layer is a matte layer, it is difficult to form an image on the surface of the surface coating layer by printing with a conventional inkjet printing machine, but the packaging material for a power storage device of the present invention uses laser light. Since the image is formed by the irradiation of the above, a clear image can be formed.

Examples of the additive include fine particles having a particle size of 0.5 nm to 5 μm. The material of the additive is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the additive is also not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a balloon shape. As additives, specifically, talc, silica, graphite, kaolin, montmoriloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, Neodium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high Melting point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel and the like can be mentioned. These additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. Further, the additive may be subjected to various surface treatments such as an insulation treatment and a highly dispersible treatment on the surface.

The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a two-component curable resin for forming the surface coating layer 6 to one surface of the base material layer 1. When the additive is blended, the additive may be added to the two-component curable resin, mixed, and then applied.

Further, when the surface coating layer 6 is provided, the surface coating layer 6 is transparent or translucent to the extent that the laser light is transmitted from the viewpoint of appropriately irradiating the adhesive layer 2 of the packaging material 10 for the power storage device with the laser light. Is preferable. In addition, transparent and translucent include colored transparent and colored translucent.

The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above-mentioned functions as the surface coating layer 6, and examples thereof include about 0.5 to 10 μm, preferably about 1 to 5 μm.

3. 3. Method for Manufacturing Packaging Material for Power Storage Device In the method for manufacturing the packaging material for power storage device of the present invention, at least the base material layer 1, the adhesive layer 2, the barrier layer 3, and the thermosetting resin layer 4 are in this order. It is provided with a step of laminating. As described above, the adhesive layer 2 is laminated so as to be in contact with the barrier layer 3. Further, the adhesive layer 2 contains a material that enables image formation by irradiation with laser light. Details of the base material layer 1, the adhesive layer 2, the barrier layer 3, and the thermosetting resin layer 4 are as described above. Further, in the method for producing a packaging material for a power storage device of the present invention, the above-mentioned adhesive layer 5 and surface coating layer 6 can be laminated, if necessary.

Further, in the method for producing a packaging material for a power storage device of the present invention, the adhesive layer 2 is irradiated with laser light from the base material layer 1 side of the packaging material for a power storage device to form an image on the adhesive layer 2. You may. Specifically, for example, a base material layer 1, an adhesive layer 2, a barrier layer 3, an adhesive layer 5 provided as needed, and a thermosetting resin layer 4 are laminated to manufacture a packaging material for a power storage device. The adhesive layer 2 can be irradiated with laser light from the base material layer 1 side of the obtained packaging material for a power storage device to form an image on the adhesive layer 2. Further, a laminated body of the base material layer 1, the adhesive layer 2, and the barrier layer 3 is formed, and the adhesive layer 2 is irradiated with laser light from the base material layer 1 side of the laminated body to form the adhesive layer 2. An image may be formed, and then an adhesive layer 5 and a thermosetting resin layer 4 provided as necessary may be laminated on the barrier layer 3 of the laminated body to produce a packaging material for a power storage device. Details of the laser beam and irradiation conditions used for image formation are as described above.

An example of the method for manufacturing the packaging material for a power storage device of the present invention is as follows. First, a laminate in which the base material layer 1, the adhesive layer 2, and the barrier layer 3 are laminated in this order (hereinafter, may be referred to as “laminate A”) is formed. Specifically, the laminate A is formed by applying an adhesive used for forming the adhesive layer 2 to the base material layer 1 or the barrier layer 3 whose surface has been chemically converted, if necessary, by a gravure coating method or a roll. It can be carried out by a dry laminating method in which the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being coated and dried by a coating method such as a coating method.

Next, the adhesive layer 5 and the thermosetting resin layer 4 are laminated on the barrier layer 3 of the laminated body A in this order. For example, (1) a method of laminating the adhesive layer 5 and the thermosetting resin layer 4 on the barrier layer 3 of the laminated body A by co-extruding (co-extrusion laminating method), (2) separately, the adhesive layer 5 A method of forming a laminated body in which the thermosetting resin layer 4 and the thermosetting resin layer 4 are laminated and laminating this on the barrier layer 3 of the laminated body A by a thermal laminating method, (3) adhering to the barrier layer 3 of the laminated body A. An adhesive for forming the layer 5 is laminated by an extrusion method or a solution coating, dried at a high temperature, and then baked, and a thermosetting resin layer 4 is previously formed into a sheet on the adhesive layer 5. A method of laminating by a thermal laminating method, (4) Adhesion while pouring a melted adhesive layer 5 between the barrier layer 3 of the laminated body A and the thermosetting resin layer 4 which has been formed into a sheet in advance. Examples thereof include a method of laminating the laminated body A and the thermosetting resin layer 4 via the layer 5 (sandwich laminating method).

When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above resin that forms the surface coating layer 6 to the surface of the base material layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

As described above, the surface coating layer 6 / base material layer 1 / adhesive layer 2 / barrier layer 3 whose surface is chemically treated as needed / adhesive layer 5 / thermosetting resin provided as needed. A laminate composed of the layers 4 is formed, and in order to strengthen the adhesiveness of the adhesive layer 2 or the adhesive layer 5, further heating such as a hot roll contact type, a hot air type, a near infrared type or a far infrared type is performed. It may be used for processing. Examples of the conditions for such heat treatment include 1 minute to 5 minutes at 150 to 250 ° C.

In the packaging material for a power storage device of the present invention, each layer constituting the laminated body improves or stabilizes film forming property, laminating process, suitability for final product secondary processing (pouching, embossing), etc., as necessary. For this purpose, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment and the like may be performed.

4. Applications of Packaging Materials for Energy Storage Devices and Packaging Devices The packaging materials for energy storage devices of the present invention are used for packaging for sealing and accommodating energy storage device elements such as positive electrodes, negative electrodes, and electrolytes. That is, the power storage device of the present invention can be obtained by accommodating a power storage device element having at least a positive electrode, a negative electrode, and an electrolyte in a package formed of the packaging material for the power storage device of the present invention. In the packaging material for a power storage device of the present invention, an image may or may not be formed on the adhesive layer 2. With respect to the packaging material for a power storage device of the present invention in which an image is not formed on the adhesive layer 2, an image can be formed on the adhesive layer 2 after the power storage device accommodates the power storage device element. Therefore, the packaging material for a power storage device of the present invention in which an image is not formed on the adhesive layer 2 becomes an image-forming body of the power storage device.

Specifically, a power storage device element having at least a positive electrode, a negative electrode, and an electrolyte is projected to the outside of metal terminals connected to each of the positive electrode and the negative electrode in the packaging material for the power storage device of the present invention. , The peripheral edge of the power storage device element is covered so that a flange portion (a region where the heat-sealing resin layers come into contact with each other) can be formed, and the heat-sealing resin layers of the flange portion are heat-sealed and sealed. As a result, a power storage device using a packaging material for the power storage device is provided. When the power storage device element is housed in the package formed of the packaging material for the power storage device of the present invention, the heat-sealing resin portion of the packaging material for the power storage device of the present invention is inside (the surface in contact with the power storage device element). ) To form the package.

The method for manufacturing a power storage device of the present invention includes a storage step of accommodating a power storage device element having at least a positive electrode, a negative electrode, and an electrolyte in a package made of a packaging material for the power storage device, and either before or after the storage step. On the other hand, the adhesive layer 2 may be provided with a step of irradiating the adhesive layer 2 with a laser beam to form an image. As a result, a power storage device in which an image is formed on the adhesive layer 2 can be obtained. The details of the laser beam used for image formation are as described above.

The packaging material for a power storage device of the present invention may be used for either a primary battery or a secondary battery. The type of secondary battery is not particularly limited, and is, for example, a lithium ion battery, a lithium ion polymer battery, an all-solid battery, a lead storage battery, a nickel / hydrogen storage battery, a nickel / cadmium storage battery, a nickel / iron storage battery, and a nickel / zinc storage battery. , Silver oxide / zinc storage batteries, metal air batteries, polyvalent cation batteries, capacitors, capacitors, etc. Among these secondary batteries, lithium ion batteries, lithium ion polymer batteries, and all-solid-state batteries can be mentioned as suitable application targets of the packaging material for power storage devices of the present invention. That is, in the lithium ion battery and the lithium ion polymer battery, a packaging material having a laminated structure in which a base material layer, a barrier layer, a heat-sealing resin layer and the like are laminated is preferable as in the packaging material for a power storage device of the present invention. The packaging material for a power storage device of the present invention can also be suitably used for these batteries. Further, in particular, the all-solid-state battery causes friction on the outer layer surface during expansion and contraction, pressure restraint, etc., and is easily peeled off by conventional printing. Therefore, the packaging material for a power storage device of the present invention can be preferably used.

The present invention will be described in detail below with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

(Examples 1-10 and Comparative Example 1-2)
<Manufacturing of packaging materials for power storage devices>
A biaxially stretched nylon film (thickness 15 μm, light transmittance of 1067 nm of 80% or more) as a base material layer and an aluminum alloy foil (thickness 35 μm) as a barrier layer were prepared, respectively. Further, as a resin composition for forming an adhesive layer for adhering them, a resin composition having the composition shown in Table 1 was prepared. As the resin composition, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) was used, and as a material capable of forming an image by irradiation with laser light, a bismuth compound (bismuth oxide) and carbon black were used. A resin composition forming an adhesive layer (thickness 3 μm) is applied to one surface of the barrier layer by the dry laminating method, and a base material layer is laminated on the resin composition by the dry laminating method. By carrying out the aging treatment, a laminate of the base material layer / adhesive layer / barrier layer was prepared. Both sides of the aluminum alloy foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum alloy foil is carried out by a roll coating method on both sides of the aluminum foil so that the coating amount of chromium is 10 mg / m ² (dry mass) in a treatment liquid composed of phenol resin, chromium fluoride compound, and phosphoric acid. It was carried out by applying to and baking. Next, on the barrier layer of the laminated body, maleic anhydride-modified polypropylene as an adhesive layer (arranged on the barrier layer side, thickness 15 μm) and random polypropylene as a thermosetting resin layer (arranged on the innermost layer side, By laminating (thickness 20 μm), the adhesive layer and the thermosetting resin layer are laminated on the barrier layer, respectively, and the base material layer / adhesive layer / barrier layer / adhesive layer / thermosetting resin layer is formed. A packaging material for a power storage device, which was laminated in order, was obtained.

(Image formation by laser irradiation)
The adhesive layer is irradiated with the laser light from the base material layer side of the packaging material for each power storage device obtained above so that the optimum output of the laser light (W (2000 mmsec)) in Table 1 is obtained. As the laser light irradiation device, a fiber laser machine (LP-Z250 manufactured by Panasonic Device SUNX Co., Ltd., wavelength 1060 nm) was used, the scan speed was 2000 mm / sec, the pulse period was 40 μs, and the character size was 1 vertical. The image was formed under the conditions of 5.5 mm, width 1.5 mm, character width 1.1 mm, character line width 0.3 mm, and character content "BEFMOQRWXUVYI1346890 +-".

(Image formation evaluation)
For each packaging material for power storage devices that had undergone the above-mentioned "image formation by irradiation with laser light", the packaging material for power storage devices was visually observed from the base material layer side, and image formation evaluation was performed according to the following criteria. The results are shown in Table 1.
A: All characters can be deciphered B: Except for some characters can be deciphered C: All characters cannot be deciphered

(Evaluation of deterioration of base material layer due to laser light irradiation)
For each packaging material for a power storage device that has undergone the above-mentioned "image formation by irradiating a laser beam", a cross section in the thickness direction of a portion where an image is formed is acquired (the cross section is the entire packaging material for a power storage device). Deterioration of the base material layer by observing the cross section of the base material layer (the position where the BEF of the character content is formed) with a laser microscope (magnification is 1000 to 5000 times) (obtained by cutting in the thickness direction). Was evaluated according to the following criteria. The results are shown in Table 1.
A: No cracks in the base material in cross-section observation B: 1 to 3 cracks in the base material in cross-section observation C: 4 or more cracks in the base material in cross-section observation

(Peeling strength between the base material layer and the barrier layer)
Each of the packaging materials for electricity storage devices (those not irradiated with laser light) obtained by the above-mentioned "manufacturing of packaging materials for energy storage devices" was cut into a size of 100 mm in length and 15 mm in width to prepare a test sample. Next, using a tensile tester (Autograph manufactured by Shimadzu Corporation), the space between the base material layer and the barrier layer of each test sample was set under the conditions of a tensile speed of 200 mm / min, a peeling angle of 180 °, and a chuck distance of 50 mm. The peel strength (N / 15 mm) was measured by peeling in the length direction. The results are shown in Table 1.

The peel strength (N / 15 mm) of the packaging material for a power storage device manufactured in the same manner as in Example 2 was measured in the same manner except that both sides of the aluminum alloy foil were not subjected to chemical conversion treatment. It was .92 N / 15 mm. From this result, it can be seen that the peel strength between the base material layer and the barrier layer is further improved by applying the chemical conversion treatment to the surface of the aluminum alloy foil.

The packaging materials for power storage devices of Examples 1 to 10 are composed of a laminate having a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order, and the adhesive layer is a barrier layer. It is in contact with the adhesive layer and further contains a material that enables image formation by irradiation with laser light. In the packaging materials for power storage devices of Examples 1 to 10, laser light is applied to the adhesive layer even though a layer containing a material capable of forming an image is provided between the base material layer and the barrier layer. Since the image is suitably formed by the irradiation of (the minimum output of the laser beam capable of appropriately forming the image is not too large), high adhesion between the base material layer and the barrier layer is provided, and the laser beam irradiation is performed. It can be seen that the deterioration of the base material layer 1 due to the above is suppressed. On the other hand, in the packaging material for the power storage device of Comparative Example 1, the adhesive layer does not contain a material that enables image formation by irradiation with laser light, and the minimum output of laser light capable of appropriately forming an image is too large. Although the image was formed, the deterioration of the base material layer was remarkable. In the packaging material for the power storage device of Comparative Example 2, since the output was half the minimum output of Comparative Example 1, deterioration of the base material layer was suppressed, but appropriate image formation could not be performed.

FIG. 4 shows an SEM image (a portion irradiated with a laser) of a base material layer (biaxially stretched iron film) / adhesive layer / barrier layer (aluminum alloy foil) in the packaging material for a power storage device of Example 1. An image of a cross section observed with a scanning electron microscope) is shown. In the SEM image of FIG. 4, the upper white layer is an aluminum foil, the thin black layer immediately below it is an adhesive layer, and the layer directly below it is a biaxially stretched nylon film. It can be seen that the layers are raised by the sublimation of carbon black in the portion of the adhesive layer irradiated with the laser beam.

(Comparative Example 3)
An ink containing 50% by mass of bismuth oxide in urethane binder resin is applied to the surface of one side of a biaxially stretched nylon film (thickness 15 μm) as a base material to a thickness of 0.2 μm, and a printing layer is applied. Was formed. An aluminum alloy foil (thickness 35 μm) was prepared as a barrier layer. Further, as a resin composition for forming an adhesive layer for adhering them, a resin composition having a urethane-based resin was prepared. By the dry laminating method, a resin composition forming an adhesive layer (thickness 3 μm) is applied to one surface of the barrier layer, and the printed layer side of the base material layer is dried over the resin composition. A laminated body of a base material layer / a printing layer / an adhesive layer / a barrier layer was produced by carrying out an aging treatment after laminating with the above. Both sides of the aluminum alloy foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum alloy foil is carried out by a roll coating method on both sides of the aluminum foil so that the coating amount of chromium is 10 mg / m ² (dry mass) in a treatment liquid composed of phenol resin, chromium fluoride compound, and phosphoric acid. It was carried out by applying to and baking. Next, on the barrier layer of the laminated body, maleic anhydride-modified polypropylene as an adhesive layer (arranged on the barrier layer side, thickness 15 μm) and random polypropylene as a thermosetting resin layer (arranged on the innermost layer side, By laminating (thickness 20 μm), the adhesive layer and the thermosetting resin layer are laminated on the barrier layer, respectively, and the base material layer / printing layer / adhesive layer / barrier layer / adhesive layer / thermosetting property. A packaging material for a power storage device in which resin layers were laminated in order was obtained. As a result of measuring the peel strength of the obtained packaging material for a power storage device in the same manner as in Example 1-10 and Comparative Example 1-2, it was 2.15 N / 15 mm.

(Evaluation of application to all-solid-state batteries)
As described above, the all-solid-state battery causes friction on the outer layer surface during expansion and contraction, pressure restraint, etc., and is easily peeled off by conventional printing. Whether or not the packaging material for the power storage device obtained in Examples 1 to 10 can be suitably used for an all-solid-state battery was confirmed by the following method. Using AB-301 COLOR FASTNESS RUBBING TESTER (Gakushin type friction fastness tester AB-301 COLOR FASTNESS RUBBING TESTER (TESTER SANGYO CO., LTD.)), A load of 300 g, a base layer surface with steel wool. After 10 reciprocations, the surface of the base material layer was visually confirmed. The test speed was SPEED CONTROL 100 (corresponding to a maximum speed of 30 cpm x 100% = 120 mm / s), a moving width of 100 mm, a load of 300 g, and a sample size of 250 mm (MD) x 2.5 mm (TD). As a result, it was confirmed that the packaging materials for power storage devices of Examples 1 to 10 did not have the print peeled off and could be suitably used as the packaging material for all-solid-state batteries. On the other hand, the packaging for a power storage device produced in the same manner as in Comparative Example 3 except that the stacking position of the print layer is outside the base material layer (that is, the outermost layer of the packaging material for the power storage device is the print layer). When the material was evaluated for application to all-solid-state batteries in the same manner as in Examples 1 to 10, it was confirmed that the printed layer was peeled off and it was not suitable for application to all-solid-state batteries.

1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Thermosetting resin layer 5 Adhesive layer 6 Surface coating layer 10 Packaging material for power storage devices

Claims (12)

A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package made of a packaging material for the power storage device.
The packaging material for a power storage device is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order.
The adhesive layer is in contact with the barrier layer and is in contact with the barrier layer.
The adhesive layer is a power storage device containing a material capable of forming an image by irradiation with laser light. The power storage device according to claim 1, wherein the adhesive layer contains 0.1 to 50% by mass of the material whose image can be formed by irradiation with laser light. The power storage device according to claim 1 or 2, wherein the material capable of forming an image by irradiation with a laser beam contains a bismuth-based compound. The power storage device according to any one of claims 1 to 3, wherein the material capable of forming an image by irradiation with a laser beam contains a black pigment. The power storage device according to any one of claims 1 to 4, wherein an image is formed on the adhesive layer. The power storage device according to any one of claims 1 to 5, wherein the adhesive strength between the base material layer and the barrier layer is 3N / 15 mm or more. The power storage device according to any one of claims 1 to 6, wherein an image is formed on the adhesive layer. The power storage device according to any one of claims 1 to 6, wherein an image visible from the outside is formed. It is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order.
The adhesive layer is in contact with the barrier layer and is in contact with the barrier layer.
The adhesive layer is a packaging material for a power storage device, which comprises a material capable of forming an image by irradiation with a laser beam. At least, it includes a step of laminating a base material layer, an adhesive layer, a barrier layer, and a thermosetting resin layer in this order.
The adhesive layer is in contact with the barrier layer and is in contact with the barrier layer.
The adhesive layer contains a material that enables an image to be formed by irradiation with a laser beam.
A method for manufacturing packaging materials for power storage devices. A storage step of accommodating a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte in a package made of the packaging material for a power storage device according to claim 9.
A step of irradiating the adhesive layer with a laser beam to form an image before or after the accommodating step.
A method of manufacturing a power storage device. The method for manufacturing a power storage device according to claim 11, wherein the laser light is a YAG laser light, a YVO ₄ laser light, or a fiber laser light.